The Imperium of Man is the galactic empire under which the majority of humanity is united. The founder and nominal ruler of the Imperium is the god-like Emperor of Mankind, the most powerful humanpsyker ever known.

The Imperium is the largest and most powerful political entity in the galaxy, consisting of at least a million worlds which are dispersed across most of the galaxy. An Imperial planet might be separated from its closest neighbour by hundreds or thousands of light years. As a stellar empire, the size of the Imperium cannot be measured in terms of contiguous territory, but only in the number of planetary systems in its control.

Several aliens and forces - the forces of Chaos, Tyranids, Eldar, Dark Eldar, Orks, Tau, Necrons - challenge the supremacy of the Imperium. From within, the Imperium is threatened more insidiously by rebellion, mutation, rogue psykers, and subversive cults. Without the protection of the Imperium, mankind would fall prey to the countless perils that threaten it.

History of the Imperium

The Imperium was founded by the Emperor, also called The Immortal Emperor, God-Emperor, and the Master of Mankind, at the end of the Age of Strife - a very long period of anarchy, war, and destructive regression which brought humanity to the brink of destruction and reversed the technological progression made during the Dark Age of Technology. In the Unification Wars, the Emperor led his proto-Astartes known as Thunder Warriors to victory in unifying Terra for the first time in millennia.

The rebellion was fought across the galaxy. Horus, seeking to achieve a swift and decisive victory, led most of the traitor forces in a direct strike at the capital of humanity, in the Battle of Terra. In the final decisive battle between the Emperor and the Arch-Traitor, Horus was slain, leading to the breakup of the rebellion and the exile of the traitors to the Eye of Terror. However the Master of Mankind was himself mortally wounded. According to his instructions he was placed on the life-preserving Golden Throne, where, for nearly ten thousand years, he has remained. Though physically a carcass incapable of movement or communication, his omnipotent will extends across the million worlds of the Imperium, beaming the psychic energy of the Astronomican, soul-binding psychic humans and struggling against the daemons of the Warp. He endures by his undying will, and by the sustenance that only the souls of sacrificial psykers can provide. By the numberless masses of humanity he is worshiped as a god.

The immediate period following the Heresy, The Scouring and Age of Rebirth, saw the Imperium slowly rebuild its might and control over the domain of man. It also saw the last of the Emperor's loyal Primarchs either fall in battle, become gravely wounded, or disappear altogether. Nonetheless in the subsequent age known as The Forging, the Imperium enjoyed a period of growth and expansion.[3e] The Imperium's period of relative peace ended abruptly in mid-M32 when an OrkWarboss known only as The Beast launched the greatest Waaagh! ever encountered. The Beast was only halted at great cost by the Adeptus Astartes.

The effects of The Waning ultimately culminated in late M41, known as the Time of Ending. Here the exhausted Imperium not only faced rejuvenated old threats, but also terrifying new enemies like the Tyranids and Necrons as well new smaller but dynamic alien empires such as the Tau, Noisome Reek, and Ulumeathic League. Beset on all sides by heresy and alien invasion, the future of the Imperium seems bleak.[3e] The Black Crusade saw both the destruction of Cadia and the formation of the Great Rift, which has effectively split the Imperium in two. However some hope has been renewed thanks to the rebirth of the Primarch Roboute Guilliman, who has launched the Indomitus Crusade to reclaim worlds lost within the Dark Imperium.

Political Structure of the Imperium

The Imperium is still nominally ruled by the Emperor of Mankind. However, since his ascension to the Golden Throne, the duty of actually ruling the Imperium falls to the Senatorum Imperialis - the Imperial Senate, formed by the twelve High Lords of Terra. The identities and responsibilities of these High Lords may vary, as individuals inevitably die and their influence grows and wanes, but its members are always the leaders and representatives of the most powerful Imperial organisations.

The Administratum - Responsible for administrative functions, it is the largest division, numbering countless scribes and petty officials. It administers the Imperium at every level, assessing tithes and taxes, conducting population censuses, recording and planning. It consists of innumerable subdivisions, offices and departments.

The Inquisition - A secret police and internal affairs organization, they are responsible for investigating any potential threat to mankind or the Imperium. Its agents hunt down heretics, traitors, alien infiltrators and even daemons. They necessarily exist beyond the Adeptus Terra's authority, as part of the Inquisition's role involves rooting out corruption and gross incompetence from the Imperium itself. They answer only to the Emperor and to themselves.

Imperial Domain

The disparate and widespread nature of Imperial territory means that a strongly centralised government would be unfeasible. The Imperium divides the galaxy into five administrative zones called Segmentae Majoris:

Ultima Segmentum - the largest province of all; its furthest extents are beyond the range of the Astronomican.

The Segmentae are the Imperium's primary administrative division. Each is divided into sectors, which are areas of space. The sectors in turn consist of subsectors, each containing a number of star systems. These divisions and subdivisions are levels forming an administrative hierarchy. Each Segmentum Commander oversees his Sector Commanders, who in turn oversees Subsector Commanders, who oversee the individual Planetary Governors. The higher ranks in this system are usually combined with a basic planetary governorship as well as interplanetary duties. This system is the means by which the Imperium maintains control of the separate planets that comprise it.

Planetary Classification

Due to its vast magnitude, the Imperium can afford for entire worlds to become specialised places where a majority, perhaps even the entirety, of the population is devoted to a single task. This could be heavy industry, military training, manufacturing, mining or agriculture. Planet-wide dedication serves to simplify logistics and increase outputs.[7] While not all Imperial worlds can be classified, the most commonly encountered types are:

Planetary Administration

Because of the distances involved and the unstable nature of Warp communication, Planetary Governors generally operate very autonomously. This allows quite a lot of variation in the regional governments. Most governorships are hereditary, but it is also possible for a planet to have an elected Planetary Governor, a tyrant Governor who rules by force of arms, or anything in between. So long as the Governor fulfills his duties to the Imperium, his rule will generally be accepted by the higher authorities. A rare few Planetary Governors preside over feral or medieval worlds where the Imperium has not, for whatever reason, seen fit to introduce modern technology. These Governors are often isolated from their subjects, sometimes even living on orbital installations, only interfering to control mutation and psykers, as well as to collect the modest tithes these planets pay.

The Imperial duties of a Planetary Governor include paying the planetary tithe to the Administratum, controlling psykers, mutation and heresy among the population, defending the planet and putting down rebellions against the local government (and thus against the Imperium). A serious responsibility is the maintenance of an adequate planetary defense force capable of defending the planet in the event of invasion. The Planetary Defence Forces (abbreviated to PDF) are expected to defeat attacks from minor foes, and in the case of major invasions to hold out until reinforcements arrive, which could take a period of months or even years.

Rebellion

The Imperial creed maintains that all of humanity must be brought into and kept within the Imperium. Several Imperial organisations are permanently occupied with suppressing any possibility of rebellion before they have a chance of developing. The common worship of the Emperor holds mankind together and instills loyalty towards the Imperium. Rebellions and uprisings on Imperial planets nonetheless remain constant. The nature and causes of a rebellion can fall into several categories: the government of an Imperial world may decide to secede from the Imperium, or may attempt to overthrow the local Imperial government. In the most insidious of cases the rebellion may be brought about by xenos or Chaos influence. In the more prosaic cases however, a government established through rebellion is not necessarily opposed by the Imperium, so long as it accedes fully to Imperial authority.[2]

Besides outright war, there are many ways a rebellious world may be brought back into the Imperium. With its more secretive organisations, the Imperium is fully capable of carrying out subvert methods of restoring Imperial rule, including assassination, popular agitation, economic sabotage and terrorism. Sometimes a rebellion can be subdued by the removal of a single individual. Pro-Imperial groups or other anti-government forces can be infiltrated or supported.[1]

Culture

While types of regimes and cultures differ greatly from world to world, there are commonly shared values and policies maintained by the Imperial central government. The worship of the Emperor as a god and the need for subject planets to pay the Imperial Tithe are rigidly enforced by agencies such as the Ecclesiarchy, Adeptus Arbites, and the feared Inquisition.[3a] In addition, the Imperium is militantly xenophobic and will annihilate entire non-human species. Besides aliens, Mutants and psykers also face ruthless persecution[3c], though certain types of Abhumans such as Ogryns and Ratlings are tolerated. The Imperium views their violently xenophobic, anti-mutant, and anti-psyker policies as necessary for the survival of the human race amid a galaxy of violent aliens and dark gods.[3b][3c]

In addition to aliens, mutants, and psykers, most forms of robotics and artificial intelligence are outlawed in the Imperium. This taboo was inherited from human civilizations of the Dark Age of Technology, who were nearly annihilated at the hands of the legendary Iron Men.[6] Thus while certain forms of robotics such as Servitors and Machine Spirits are sanctioned, any kind of true artificial sentience is declared to be a heretical Abominable Intelligence.

Imperial Languages

Low Gothic is the common tongue of the Imperium, spoken on most Imperial planets as a first or second language. Imperial worlds have inevitably developed their own dialects of Low Gothic over time. High Gothic (represented as Latinised English) dates from an age before the Imperium, and is used solely as a hieratic tongue by the divisions of the Adeptus Terra, the Inquisition and the Ecclesiarchy.

Religion

The Imperium's state religion, the Imperial Cult, is the one and only faith under Imperial law. While forms of worship may differ, they share a common belief that the Emperor is a God and the master of Mankind. This state religion is overseen by the Ecclesiarchy, the Imperial church and one of the most powerful and influential organizations among humanity. Any kind of deviation or apostasy against the Imperial Cult is classified as heresy, punishable by death.[3d]

However other illegal faiths are practiced covertly by denizens of the Imperium, most notably among persecuted classes such as mutants. Unfortunately, it is common that often times this involves worship of the Dark Gods.[3c]

Economy

Wealth in the Imperium is distributed highly unequally, and those below are expected to serve those above. The Imperium primarily collects its wealth through its Tithes maintained on each world. Many types of currency in the Imperium exist, such as Credits[8], Crowns[9], and Thrones[10]. Often goods, resources, and manpower are substituted as currency on a planetary level.[3e]

Imperial Dating System

The Imperial dating system is based upon "Anno Domini", although expressed in rather different terms. A full dating code consists of a "check" number, "year fraction" number, "year" number, and the millennium.

The millennium is a suffix, represented by an "M" and the millennium number.

The three digits preceding the millennium is the year within the millennium, running from 001-000 (one thousand). For example 0150930/M32 is the year 930 of the thirty second millennium (31,930 A.D.).